1. Field of the Invention
The present invention relates generally to wireless communications.
2. Background Art
According to the IEEE (Institute of Electrical and Electronics Engineers) 802.11 standard, WiFi devices may operate on eleven channels (channels 1 through 11) located in the 2.4-GHz ISM (Industrial, Scientific, Medical) band, which spans from 2400 MHz to 2483.5 MHz. Each WiFi Channel is 22 MHz wide, and consecutive WiFi channels are separated by 5 MHz. Channels 1, 6, and 11 are non-overlapping channels centered at 2412 MHz, 2437 MHz, and 2462 MHz, respectively.
The WiMAX (Worldwide Interoperability for Microwave Access) forum has published three licensed spectrum profiles (2.3 GHz, 2.5 GHz, and 3.5 GHz) for IEEE 802.16e WiMAX devices. The 2.5 GHz spectrum profile corresponds to the Federal Communication Commission (FCC) Broadband Radio Service (BRS) band (2496 MHz to 2690 MHz). The FCC BRS band is divided in 5.5-MHz or 11-MHz channels with corresponding 5-MHz and 10-MHz WiMAX system bandwidths.
Accordingly, in certain scenarios, the guard band between WiFi and WiMAX operating bands may be less than 20-MHZ (e.g., in the case of WiFi operating on channel 11 and WiMAX using an 10-MHz channel centered at 2496 MHz, only 18 MHz separate the operating channels). Thus, when a WiFi transceiver and a WiMAX transceiver operate in close proximity to each other, the two transceivers may interfere with one another in the absence of synchronization. Accordingly, there is a need to ensure coexistence between WiFi transceivers and WiMAX transceivers operating in close proximity to each others.
The present invention will be described with reference to the accompanying drawings. Generally, the drawing in which an element first appears is typically indicated by the leftmost digit(s) in the corresponding reference number.